I have found a small (approx 1/8" to 3/16") white tablet. It is imprinted with 021 on one side and a symbol on the opposite side that looks a bit like a percent sign. Not exactly like one, as the rounded shapes are not entirely round and appear to actually be a part of the line.

Can anyone help? My mother found this pill on her floor after having some company over on Christmas and is quite concerned about what it might be.