The Onion had a list of humorous drug side-effects a couple of months ago. My favorite? “Highness”
The key word there is may. I doubt there is a medicine out there that works for all people, and some will have the opposite of the intended effect. Certainly if the medicine is making you worse, you want to tell the doctor.
People who are in drug tests don’t magically stop having the normal problems of day to day living. That means that during the test, the subjects may get colds, the flu, headaches, mild food poisoning, etc. Some of them may already be prone to things like diarrhea. Also, medical problems aren’t static - a problem or disease will get better or get worse on its own. But they have to report any symptom that happens, so that effectiveness and side effects can be determined. This is one of the reasons for a double-blind study, to filter out the effects of the drug from the effects of everyday life.
Bwa hahahahahahah! <snort> 
That was hilarious… Earl Grey coming out of your nose at 8 in the morning is pretty funny too. 
Zyada, I’m actually quite aware of the details you brought to light, and I thank you for the edification, but I just find that type of thing so damn amusing.
I consulted my pharmaceutical expert (Jason, the newly graduated pharmacy tech over at Wal-Mart) and found out about a few more potential side effects:
oozing (generalized)
vague sensation of being alive
crankiness
all-consuming evil thoughts and deeds
90 degree angular defect in penis
fervent punctuality
vociferous syndrome, type 2 (non-gregarious)
feeling better than you ever thought you could (the drug boys really hate that one)
inability to identify Coke vs. Pepsi
Is that another one of the side effects? innocent look
How about:
“Side effects may include the desire to watch Mary Kate and Ashley videos.”