Could it be Tamoxifen causing this?


I wonder if anyone can help? I have been on Tamoxifen for 6 months now and swim quite regularly. Recently I have been trying to change my stroke from breast-stroke to front-crawl. In doing this I have accidentally swallowed some pool water twice now (not my preferred beverage or recommended!) and on each occasion have been ‘violently’ ill during the night. I have a ‘cast-iron’ constitution and hardly ever suffer with gastric issues and I never experienced this prior to my dx with BC and subsequent treatment and so wondered if it could be either the Tamoxifen or lasting effect from chemo? I’m now really quite nervous of trying again in case I’m unwell. I know it’s a bit bizarre but has anyone else experienced anything similar?

Hi Twinny2

I have not been swimming (not brave enough to wear a swimsuit in public) but since being on Tamox have suffered nausea most days. I think it is Tamox because the nausea briefly went between chemo and starting it. I am violently ill after the smallest measure of alcohol, sadly i find lots of things I used to eat disagree with me or taste strange!

Maybe i am wrong?


Jane x

Hi Twinny and Jane,
I’ve been on Tamoxifen for over a year now, and swim regularly and I haven’t had anything like this happen. Although i do find I can’t drink much alcohol at all before feeling rather queasy (like 2 thirds of a glass of wine!). I wonder if it’s the result of chemo killing off the ‘good bacteria’ in your guts, so you have less defences. I’ve had a couple of stomach bugs and a terrible bout of food poisoning since chemo, and like you, used to have a cast iron stomach.
After chemo, and now on tamoxifen and herceptin, it’s hard to decide which one’s the culprit.
Jacquie x


Thanks for your replies Jacksy and Jane. I haven’t been brave enough to try front crawl again, just in case I swallow more water and have another bad reaction. However I may try again at the weekend as a trial to see…yikees not looking forward to it. But at least then I may find out once and for all, even if I don’t find out if it’s the Tamoxifen or chemo that has caused it. I do however consider myself very lucky that it isn’t alcohol upsetting me, as pool water can be avoided!

Hi Twinny
I would stick to breast stroke, I am pretty sure a strong constitution or not, pool water is full of unwanted microbes, bacteria etc. or overloaded with chlorine, yuck. So breaststroke with mouth SHUT or at least spit not swallow. You could always try backstroke, your only danger there are possible collisions with fellow swimmers, walls or ropes.
As for the Tamoxifen, I cannot comment, I suppose it has to be if concerned ask your doc.
Happy swimming.
All the best Alice.