Hives thirty minutes after taking probiotics...how long till probiotic is out of system?

Variable but...: This is very unusual though possible; however, there is a good chance the timing was a coincidence and the hives are caused by something else. The average amount of time is about 2 days but you could speed this process by taking 1-2000 mg of vitamin C until he has a bowel movement. The Vitamin C also helps hives. Can also try Benadryl or another antihistamine.

Probiotics: It may take 24-36 hours to clear your system of probiotics