Snowdrops contain the compound Galantamine, which is used in the treatment of Alzheimers.
The leaves of snowdrops often appear through the snow in January. The leaf spikes are gray/green in colour, and the white flowers hang from wide flat stems.
Leave them be. The leaves will die back after flowering. The bulbs will form clumps which can be separated if they get to big. Split clumps or plant new bulbs in autumn.