Many people believe they are allergic to chocolate. However, true chocolate allergies, in which a person is allergic to cocoa, are very rare. Cocoa is made by fermenting, roasting and then grinding seeds from the cocoa tree. While they originated in Central America cocoa trees are now grown in tropical climates around the world.

Many reactions to chocolate are caused by an intolerance or allergy to one or more of the other ingredients or food additives in chocolate. These include soy lecithin, milk, corn syrup, gluten, nuts, flavorings and dyes. While they are not intentional additives, trace amounts of rat and mouse droppings, as well as cockroach and other insect parts, are occasionally found in some chocolates.

Chocolates from countries outside the United States often have less stringent regulations for listing trace ingredients in foods.

Food allergies to cocoa or other chocolate ingredients can cause a variety of different symptoms including:

• Headache
• Heartburn
• Rectal itching
• Hives
• Skin rashes
• Confusion
• Breathing problems

Chocolate allergies may also trigger asthma attacks in people with asthma who are sensitive to one or more chocolate ingredients.

Chocolate quality is a factor in the number and amount of additives. Generally the higher the quality of chocolate (indicated by the percentage of cocoa liquor and cocoa butter) the lower the chance of other additives. Mass–produced lower quality chocolate has less cocoa butter and more milk, soy lecithin, gluten and flavorings. The ingredients in chocolate will be displayed on the product label.

Some people are sensitive to naturally occurring chemicals in chocolate like caffeine, theobromine and phenylethylamine. These chemicals may cause mood swings and headaches in some people. The reactions to these naturally occurring chemicals in chocolate are not allergies. 

A physician may perform a number of tests to determine if a person is allergic to chocolate. These may include skin tests and blood tests.

When treating a chocolate reaction, a physician will first determine whether the patient has a food allergy, food intolerance, or another condition producing similar symptoms. The physician may recommend dietary changes to reduce or eliminate reactions.

People sensitive to the chemicals or additives in chocolate can avoid unpleasant symptoms by eliminating chocolate and/or the specific additives from their diets. Medications, such as anti-diarrheals for gastrointestinal symptoms or creams to relieve skin rashes, may be prescribed.

People allergic to the ingredients in chocolate may experience breathing problems, or other symptoms related to asthma attacks or severe allergic reactions. These symptoms can be relieved through taking an antihistamine, corticosteroid or bronchodilator medications.