some labs purity standards aren't always up to par.you will hear alot of guys say when they start mexican shit that they get a "juice flu".i get it sometimes.but i just keep taking and it goes away in a day or two.if i get the flu like feelign from it i just take theraflu for liek two days and i feel better.try not to take antibiotics because then when you get the REAL flu your body may have a tolerance to them when you need them