I was constipated for about a week and a half, so I started taking Metamucil for four days. The constipation went away for the most part, but now I've had really bad headaches for about three days. Is there a connection? Thank you.
Maybe some of the ingredients that are in Metamucil trigger a Migraine attack for some people. I haven't heard this before, but that doesn't mean it isn't possible. You can also have an allergic reaction.
Constipation can also cause headaches: http://www.healthcentral.com/ibd/h/can-constipation-cause-headaches.html
Could it be dehydration? You really have to drink a lot of water with Metamucil....I had a friend who's Dr had him taking it regularly (he was in a wheelchair, constipation is a typical problem), and if he didn't drink at least two glasses of water with it he got a headache.