Dehydration is one of the most worrisome complications of diarrhea in children. Mild diarrhea usually doesn't cause significant fluid loss, but moderate or severe diarrhea can. Severe dehydration is dangerous; it can cause seizures, brain damage, even death. Know the signs of dehydration.
Cough and cold medications and decongestants may cause the eyes to dilate. In general, any medication that is a stimulant may cause the eyes to dilate. While it's not particularly common, this could include ADHD medications such as Adderall or Ritalin. Of course, certain illegal drugs do this as well, such as cocaine.
Normal pupils get smaller, or constrict, with bright light levels, and enlarge, or dilate, with low or dim light. Changes in pupil size also occur with focusing your eyes and in response to emotion. Pupil dilation can also result from a variety medications or drugs. Eye care professionals often take advantage of eye drops that cause pupil dilation so they can get a better look at the back of the eye during an eye exam. In most other circumstances, pupil dilation from medications or drugs is considered a side effect.