4. Diet pills
These “miracle” weight loss pills often don’t deliver the results they promise, but can instead put you in hot water with an employer. One of the main ingredients in diet pills, called phenylpropanolamine, can cause a false positive result.
Over the counter weight loss drugs, according to Livestrong, may show up in tests as evidence of amphetamines in legal drugs for conditions such as ADHD, as well as in street drugs such as Crystal Meth (methamphetamine) and speed.
5. Poppy seeds
Poppies are used to make narcotics, Livestrong noted, although the site claims that eating a poppy seed bagel is not enough to sound the alarm. Although Livestrong does not say exactly how many poppy seeds will cause problems for a drug test, « a large amount of the seeds must be consumed » for a negative effect, he explains.
The United States Anti-Doping Agency, which regulates drug testing in athletes, said that the poppies are harvested for opium which contains morphine and codeine and that sometimes the opium extract can contaminate the poppy seeds. Although the treatment removes most of the opium from the seeds, there could be a significant level of codeine and morphine in your urine for up to 48 hours after eating a harmless bagel.