I haven't experienced any negative side effects so far, besides the usual laxative effect of consuming a whole papaya.
Consuming a whole papaya with a dash of honey mixed in a blender first thing in the morning on my non-fasting days, proceeded by meals mixed with a crushed bulb of raw garlic really helps me.
Papaya and its seeds seem to be one of the most powerful natural anti-Helminths I've come across.