Gastric distress is caused by contaminated water.
To help prevent this problem, insist on obtaining
bottled water with the seal still intact. Use this
water for brushing teeth. Avoid ice in drinks, and
avoid salads and raw vegetables that may not have been
washed in purified water. If you do start having
problems, try over-the-counter aids such as Imodium or Cipro Flaxin.