Question

How are gastrointestinal problems cured?

Answer 1

They aren't, but you can relieve them by resting, forgoing food and drinking plenty of water.

Explanation:

See this answer for more information, but basically gastrointestinal pain can't be cured, as it involves a wide-reange of problems. The good thing is that although everyone gets it, it will mostly cure itself in 3-4 days. If symptoms persist however, always seek a doctor.

Plenty of water, rest, and the cutting back of most food can help gastrointestinal pain, as well as some antibiotics (although this may be sketchy, depending on the person).
http://www.livestrong.com/article/86606-treat-gastrointestinal-problems/

I hope I helped!