If possible, always try to get your bud from a trusted source.

There's so much floating around out there that you have no idea how it was grown, what kinds of fertilizers and chemicals were used, or how well that stuff was flushed from the plant prior to harvest.

Smoking nasty chemicals could definitely make anyone feel ill and puke after too many bowls of it. Kinda scary to think about it actually. How many toxic chemicals have you consumed from the mystery buds you buy on the street? There are no standards for quality control. Consume at your own risk unless it is from a reliable source.