Guinea Pigs and Anaesthetic

This week I took Nutmeg, one of my guinea pigs, to the vet because of a lump she had on her tummy which had grown slightly bigger and harder recently. Unfortunately, we were told that it was most likely to be cancer. This horrified me although I was not surprised. But now I have to make some decisions. The vet whom we consulted suggested two options:

  1. Go through an operation and have it removed
  2. Wait until it gets very bad, ensuring she has a good life, and consider euthanasia when necessary

Number 1 – ADVANTAGES – removes the cancerous lump                                                   – Nutmeg can live a long and happy life                                                                               – Saffron doesn’t get lonely                                                                    – prevents the lump developing and getting worse

                – DISADVANTAGES – the RISK of surgery and anaesthetic on small animals                                                           – may take a long time to recover                                                                                    – problems with two guinea pigs after the operation                                                          – trauma


Number 2 – ADVANTAGES – likelihood of a relatively long time to live and be happy                                                         – prevents disadvantages from surgery                                                              – enjoying life to the full for Nutmeg and me

                – DISADVANTAGES   – Nutmeg will suffer when the lump becomes worse                                                           – she will have to be put down                                                                  – worry as it worsens

But to make a good judgement as to what to do, I feel that I must explore the risk of putting a guinea pig through surgery, especially because of the anaesthetic.

When reading on ‘The Guinea Pig Forum’, I found that most people who have had their guinea pigs put under general anaesthetic have come out successfully. The only deaths I read about were those not directly caused by the anaesthetic, but rather the problem the guinea pig was first suffering with. Furthermore, a big risk with anaesthetic is the heat loss involved when the animal is not moving so cannot maintain the correct core body temperature. This is enhanced by the large surface area to volume ratio of small animals such as guinea pigs causing the amount of heat lost to worsen. Therefore, a major concern with anaesthetic is the hypothermia which can result from it if the guinea pig’s temperature is not carefully monitored throughout and after the operation until it has completely recovered. Also, they should be treated by an experienced small animal vet who knows what they are doing. As well as this reactions could be caused by the anaesthetic resulting in unpredictable risks and infections could arise post-op if the wound has not been stitched sufficiently.

This table demonstrates the risk of animals dying when put under anaesthetics. Although initially it appears that there is not that high a risk for guinea pigs, being only 3.8%, when compared to humans, the 19000 times more likely of death within guinea pigs becomes evident as well as the fact that they are most at risk than any other animal displayed on the table, including hamsters and rats which are smaller but still appear under other small animal species.

However, I also learnt and found interesting, that different types of anaesthetic have different risks involved, some being safer than others. These I read to be Isoflurane and Sevoflurane, which are generally used and considered to be safe. Also, both are inhalation agents.


  • can contribute to hypothermia in small animals through causing vasodilation (the dilation of blood vessels, which decreases blood pressure)
  • can be irritant to the tracheal mucosa, sometimes causing animals to breath-hold even when heavily sedated (normally only a problem in rabbits)
  • provides good skeletal muscle relaxation with only mild to moderate cardiovascular and respiratory depression

  • rapid recovery


  • rapid recovery
  • potential respiratory problems in guinea pigs

In conclusion, I believe that I could safely choose to put Nutmeg under anaesthetic in order to remove the cancerous lump, however, as she is a happy piggy who does not seem to suffer nor even notice that the lump is there, I will probably not choose to go with surgery. The research I have done in order to make this decision has been very interesting and I feel that I am now satisfied in the knowledge I have gained about the processes of putting guinea pigs under anaesthetic.


9 thoughts on “Guinea Pigs and Anaesthetic

  1. I know this blog entry was made years ago but I am commenting for the learning of others. What your guinea pig most likely had was a benign lipoma that did not require surgical removal! Cancer in younger guinea pigs is rare. When they get older some can present with organ cancer in the GI cavity or lymphoma, but their risk of cancer is still MUCH lower than that or rats and hamsters. The most frequent cause of lumps in the subcutaneous tissue of guinea pigs are both benign (cannot turn into metastatic cancer that kills): trichofolliculomas and lipomas. Trichofolliculomas can sometimes cause problems by draining secretions and getting infected- for that reason sometimes the vet will surgically remove them. But many stay put on a pig for their lifetime, just requiring a drainage once or twice and cause no other problems. Lipomas are extremely common on the ventral area of guinea pigs (Peter Gurney called them “jelly beans”) and do not cause any problems at all. Your vet should never have told you your pig likely had cancer and needed surgery.

    • Thank you so much for your comment. That is really interesting and makes me glad that I chose not to go ahead with the surgery my vets suggested. Unfortunately, my gorgeous guinea pig, Nutmeg, who had the lump died about 2 years ago, but it didn’t appear to be as a result of the lump. I woke up one morning to find her ruffled and listless – she had been fine the night before but then died within the hour. I still have her sister, Saffron, who has lots of little lumps across her tummy – just like jelly beans! I also note that what you mentioned about cancer in rats is true for me. I have two pet rats and one of them, Pistachio, has a large lump near her groin which I believe is probably mammary cancer. It is growing relatively quickly but she is too old for surgery and she is still very happy, maintaining a good quality of life. Thanks again, your comment has made a great contribution to my post.

  2. I’m glad I found this blog, I’ve been quite worried because one of our guinea pigs is ill and I’m told he needs to be sedated to have an xray, at first I called and disagreed but the receptionist got back to me and said that if he doesn’t have it then the vet cannot treat him as she doesn’t know what’s wrong with him, so I’ve agreed to it, but I’m still very worried as he’s not a well guinea pig. I see the % is a bit higher for Guinea Pigs, I’m hoping that my mine isn’t the 1 in 26. Thanks for doing the blog.

    • Thank you for your comment, it is really encouraging to know that it has been useful. Be aware that sedation is not the same as a general anaesthetic. It is likely that the vet will only sedate your guinea pig if it’s only an x-ray, making him nice and sleepy but not knocking him out completely. The statistics are referring to anaesthesia so I would hope that your piggy has a much better chance than 1 in 26. It is after the x-ray when the hardest decisions will have to be made, depending on what the vet diagnoses and suggests as treatment. I really hope all goes well and your guinea pig makes it through safely. Best of luck.

  3. I have a 3 yr old male guinea pig. Recently I discovered quite a big lump under his chin/neck area. It was hard and must have been quite uncomfortable but nether less he was still eating/playing and squeaking. I realise that he probably is in pain but is braver than I thought! I took him to my vet and he said it could be an abscess from a tooth but the bacteria has spread. He took Scruffs and lanced the lump and drained it. They told me the liquid was browny red like blood with bacteria in. He said that it is possibly a tumour and said my options were to put Scruffs through surgery to remove the lump or if he is happy in his life and still acting like normal I should let him plod on and if he starts to deteriorate then think about euthanasia. I’m glad I have made the decision not to put him through the surgery as he is still himself and very happy just hate to think he’s in pain. I wish I was a Dr dolittle sometimes!

  4. thank you for this
    We have just recently had to put our beloved Spike to sleep as he wasn’t well, when we 1st took him to the vets they diagnosed pneumonia, however after not responding to the antibiotic and then not being able to eat at all for a day we took him back to the vets and they discovered a tuomour in his throat, as he was so weak they advised that it would be best for him to be put to sleep, which we did, I have been questioning whether this was the right decision or whether we should have tried the sugery(vet didn’t offer this) but this makes me see it was the right thing to do

  5. I have a 2.5 year old girl right now and she also has a lump under her chin. I took her to the vet and she said the mass might be a tumor because she tried to get a sample of the lump with a syringe, but nothing came out. She referred me to a specialist at a veterinary school, which has high tech equipment to determine what it is through variois tests, and I don’t know whether I should go. The consultation fee alone is about 200, and it could increase to over 1000 if tests are required. Being a college graduate with an minimum wage job, I can’t afford it. The vet also gave me another option, which is to just do surgery, without actual knowledge of what it is, which could run up to 600. I’m not trying to put my finances before my guinea pigs, but I’m afraid that if I do go through with the lab test and if it does require a surgery I wouldn’t be able to afford it plus the medication for post op aftercare. And the same goes for going through with just surgery. I also don’t want to subject my guinea pig to it because I don’t know how she’ll react to anything.

    I was planning on scheduling the surgery tomorrow, but I’m so glad I found this. Like what OP said, my guinea pig is fine and happy. I just have to help her eat every once in a while. I’m hoping she’ll continue to live a happy healthy life and if it has to happen, I’ll probably have to put her to sleep.

    Also to note, please please don’t let anyone you know give or receive a pet as a gift, especially when they aren’t financially stable. That’s how I got my first pig who is 3. I ended up getting my second girl because the first needed a companion. A pet is honestly the worst gift someone can give to another who is not ready.

  6. My piggie Chester has an abnormal growth on his genitals and he is having surgery to remove it today. I am very worried about my boy but I had two options. Have it surgically removed or leave it and risk him catching it on something and bleeding out. I got him as a very unwell guinea and he has come on leaps and bounds and I believe he is strong enough to get through the op I just hope I’m right. He should of died at 4 months old and he is now 10 months old and I’m so proud of how well he is doing. He is truly a little warrior and I couldn’t be more proud to call him my little piggie

  7. I have a ten year old guinea pig who has a huge tumor on his right shoulder. It has now started to open and has a scab on it. I think he is too old to have it removed, but he still seems to be happy, so I don’t want to put him down. What to do?

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