22/06/2026
Alpha-gal syndrome (AGS) is a serious, potentially life-threatening allergy to alpha-gal that can develop after a tick bite.
Alpha-gal is a molecule found in most mammals, such as cows and pigs, but not in people.
People with AGS can have an allergic reaction after eating red meat or being exposed to products containing alpha-gal.
The best way to protect yourself and your family from AGS is to prevent tick bites.
Tick bites can cause an allergic reaction to red meat, diary, and other products.
What is alpha-gal syndrome?
Alpha-gal syndrome (AGS) is a serious, potentially life-threatening allergy and tickborne disease. Alpha-gal is a molecule (galactose-α-1,3-galactose) that is naturally produced in the bodies of most mammals but not in people. It is also found in the saliva (spit) of some ticks.
When a tick bites, it can transfer alpha-gal from its saliva into a person's blood. The body's natural defenses, or immune system, can identify alpha-gal as a threat and trigger an allergic reaction. Symptoms occur after people eat red meat or are exposed to other products made from mammals. Because of this, AGS is also known as red meat allergy or tick bite meat allergy.
In the United States, the lone star tick is most often associated with AGS. A few cases of AGS have been reported following bites from blacklegged and western blacklegged ticks.
Nearly 450,000 people may be affected
More than 110,000 suspected cases of AGS were identified between 2010 and 2022. However, cases of AGS are not nationally notifiable to CDC. The actual number of AGS cases in the United States is not known, but as many as 450,000 people may be affected. More data and research are needed to understand how many people are affected by this condition.
Did you know?
Most healthcare providers recommend patients with AGS stop eating:
Red meat such as beef, pork, lamb, venison, or rabbit
Dairy products, if a person is not able to tolerate dairy
Some medicines and non-food products
Work with your healthcare provider to understand which products contain alpha-gal.
AGS is caused by tick bites, though more research is needed to understand the role ticks play in causing AGS. In the United States, AGS is primarily associated with the bite of a lone star tick, and less commonly by the bite of a blacklegged tick or a western blacklegged tick. In other countries, other tick species have been linked to AGS. In the United States, not every person bitten by a lone star, blacklegged, or western blacklegged tick will develop AGS. The reason why certain people develop AGS and others do not is not known.
Most cases of AGS have been reported in adults, but people of all ages can develop AGS.
Most reported cases of AGS in the United States occur in South, East, and Central states. These are the areas where most lone star ticks are found.
Prevention
The best way to protect yourself and your family from developing AGS is to prevent tick bites.
More ways to reduce risk
You can also take steps to protect your pets and reduce risk of tick exposure around your home.
Diagnosis
A healthcare provider diagnoses AGS by:
A physical examination
A detailed patient history
A test for antibodies your body produces in response to alpha-gal
Your healthcare provider may also recommend allergy skin testing to identify reactions to allergens like pork and beef.
Living with AGS
AGS should be managed under the care of an allergist or other healthcare provider.
Most healthcare providers recommend patients with AGS stop eating meat from mammals, such as beef, pork, lamb, venison, or rabbit. Some patients need to eliminate other sources of alpha-gal, such as dairy and certain medications. Patients can work with their healthcare provider to determine which sources of alpha-gal should be avoided.
AGS symptoms can range from mild to severe, and some may be life-threatening. People with AGS might not react to every product containing alpha-gal, and some people can experience different symptoms or reactions each time they are exposed to alpha-gal, even when it is the same product.
