So I've pretty much always had minor thrush on my tongue for as long as I can remember. Going by what causes I've read about, I don't have any cause. HIV is a cause, but I've been tested well beyond the conclusive mark, so I don't have that. Antibiotic medicines are a cause, but I don't even know the last time I've ever taken antibiotics. Not that I know of do I have a weak immune system (also a cause). I've always seemed to have a pretty healthy immune system. I almost never get sick and when I do catch a cold or something, I'm over it in a short period of time. I have heard mouthwash can cause it, which I do use. Is this true, though? Since mouthwashes are made to kill bacteria in the mouth, does it act the same as antibiotic medicines?