Prickly pear seeds can be harmful if eaten whole

A few years ago I had a severe case of constipation from eating too many prickly pears. I ate about 50 fruits in one day. The seeds all got compacted in my lower bowels and it was extremely painful. I've read reports that prickly pear seeds used to be ground into flour and eaten, and also that they are quite nutritious (as many seeds are). Sometimes I take the time to grind them into flour to eat alone or mix with other ingredients. When ground into a course meal they are easier to digest.