I have a health-related content site and I guess it's time now to put ads. Anyone knows what's the best health-related affiliate programs?
CPA networks are packed full of health/weight loss offers if that is what you mean? Otherwise Clickbank has loads of "weight loss" ebooks etc.
MoreNiche offers a very popular weight loss product - Proactol and also Aloe Vera pills - AloeRide that should work great on a health site. Just write and post reviews about them, don't only put some banners.
MoreNiche and MarketHealth. SFI is also recommended although some people consider them more like MLM than affiliate program.