Symptoms of dry beriberi include pain, tingling, or loss of sensation in hands and feet (peripheral neuropathy), muscle wasting with loss of function or paralysis of the lower extremities, and potentially brain damage and death.

Wet beriberi is characterized by swelling (edema), increased heart rate (tachycardia), lung congestion, and enlarged heart related to congestive heart failure.

Beriberi has become very rare in the United States because most foods are now vitamin-enriched, which means that a normal diet contains adequate amounts of thiamine.

As a result, beriberi now occurs primarily in patients who abuse alcohol, because drinking heavily can lead to malnutrition and poor absorption and storage of thiamine. This is the cause of "wet brain" or Wernicke-Korsakoff syndrome, which is alcohol-related brain damage affecting language and thinking.

Beriberi can also occur in breast-fed infants when the mother has an inadequate intake of thiamine. It can also affect infants fed unusual formulas with inadequate thiamine supplements.

Others at risk for beriberi include patients undergoing dialysis, patients receiving high doses of diuretics, and people in developing countries with limited diets who consume milled rice.

Neurologic symptoms are caused by degeneration of the nerve fibers and their insulation (myelin sheath). Heart failure is the most common cause of death in people with beriberi.