Gut cleanses are probably stupid but I wonder if people would benefit from taking antiparasitics prophylactically. It's not something I've ever done, but I eat sashimi pretty regularly and wonder if I should take something like praziquantel because I'm probably at risk for Japanese broad tapeworm, and the symptoms are mild enough I can't really tell without testing, but the price of actually testing is much higher than just taking a drug with a great safety profile.

For similar reasons, I also wonder about people who consume raw milk. These people are more likely to endorse ivermectin for e.g. covid, because it made them feel much better. Maybe it's possible these people aren't lying about that, but not because it cured their covid.