Some people with giardia infection never develop signs or symptoms but still carry the parasite and can spread it to others through their stool. For those who do get sick, signs and symptoms usually appear one to two weeks after exposure and may include:

  • Watery, sometimes foul-smelling diarrhea that may alternate with soft, greasy stools
  • Fatigue or malaise
  • Abdominal cramps and bloating
  • Belching gas with a bad taste
  • Nausea
  • Weight loss

Signs and symptoms of giardia infection usually last two to four weeks, but in some people they last longer or recur.

When to see a doctor

Call your doctor if you have loose stools, abdominal bloating and nausea lasting more than a week, or if you become dehydrated. Be sure to tell your doctor if you're at risk of giardia infection — that is, you have a child in child care, you've recently traveled to an area in which you know giardia infection is present, or you've swallowed water from a lake or stream.

Nov. 14, 2012