Oyster Side Effects: What to Know When Eating This Shellfish

Side Effects of Eating Raw Oysters

Raw oysters offer big health benefits, serving as an excellent source of protein, Vitamin B-12, copper, zinc, and selenium. However, they also cause thousands of people to get sick each year, according to the Centers for Disease Control and Prevention (CDC).

As filter feeders, these bivalve mollusks consume about 25 gallons of water a day. While oysters support a healthy coastline and help keep the water clean, they can also harbor pathogens that can make you sick.

Eating raw or undercooked oysters can put you at risk for an infection called vibriosis, which is caused by various strains of Vibrio bacteria in contaminated shellfish. Most healthy people who get vibriosis experience diarrhea and vomiting within 24 to 48 hours of exposure, but some cases are life threatening, with 1 in 5 people dying from the infection. People with compromised immune systems and certain chronic health conditions are more susceptible to severe reactions, according to Kaiser Permanente.

Eating raw oysters can also lead to norovirus and hepatitis A infections, according to the Virginia Department of Health. Symptoms can include vomiting, diarrhea, nausea, stomach pains, and severe weakness, as well as yellowing of the skin and eyes in hepatitis A cases.