Can Eating Too Much Chocolate Actually Kill You? Here's What We Know

You probably know of someone whose curious dog got hold of a box of chocolates and had to be rushed to the veterinarian. That's because a chemical in chocolate, theobromine, can be toxic to dogs and can cause vomiting, a racing heart rate, or restlessness. More severe poisoning could cause heart failure. Although our bodies can process theobromine, dogs are more sensitive to this chemical (per VCA Hospitals).

Yet humans can suffer from a toxic dose of chocolate, according to Popular Science. Initially, you could eat enough chocolate so that the theobromine could cause you to vomit. Eating that much chocolate might send you to the hospital for a sick stomach before a theobromine overdose. You could then feel symptoms such as an increased heart rate, excessive sweating, or headache if you have a high dose of theobromine in your system. Like caffeine, theobromine is a stimulant, and its diuretic properties might have you running to the bathroom more often. Theobromine also expands your blood vessels and causes a temporary decrease in blood pressure. But you'd need to eat hundreds of chocolate bars to get enough theobromine in your system to be fatal.

How much is a fatal dose of chocolate?

It's not likely that you could eat so much chocolate to suffer from theobromine toxicity. A toxic dose in humans is 1,000 milligrams (or 1 gram) of theobromine for each kilogram of body weight. For someone weighing 150 pounds, that's 68,000 milligrams (68 grams) of theobromine.

An ounce (28 grams) of dark chocolate with 70 to 85% cacao has 227 milligrams of theobromine and 23 grams of caffeine. To eat enough chocolate to have theobromine toxicity, you'd need to eat 300 ounces of chocolate. That's 764 squares of Ghirardelli chocolate or 85 Lindt Excellence chocolate bars. Eating just half that might make you sick just from the caffeine because 150 ounces of that same chocolate will put 3,450 milligrams of caffeine in your system. That's like drinking 34 cups of coffee in a single sitting.

Milk chocolate doesn't have as much theobromine or caffeine as dark chocolate. A standard 1.5-ounce milk chocolate bar has 90 milligrams of theobromine and about 9 milligrams of caffeine. Theobromine could reach toxic levels in your system if you eat about 755 chocolate bars.

Side effects of chocolate

While it's probably impossible to eat enough chocolate in a single sitting to kill you, eating too much chocolate can often lead to some problems, according to Medical News Today. The high sugar and fat content of many chocolate candies can lead to weight gain and tooth decay. Some people might find that certain substances in cocoa can trigger their migraines. Consumer Reports found that some brands of chocolate, such as Lindt, Trader Joe's, Hershey's, and Beyond Good, have unhealthy levels of cadmium or lead, which are heavy metals that can suppress the immune system or lead to kidney damage.

You don't need to give up on chocolate, but keep it from your pets and enjoy it for yourself in moderation. According to Johns Hopkins Medicine, the flavonols in chocolate can help your body fight free radicals that cause cell damage and inflammation. Chocolate can lower blood pressure and improve blood flow to the brain. Athletes can enjoy chocolate to help boost circulation and endurance. When choosing chocolate, be sure to look for at least 70% cocoa to enjoy chocolate's health benefits.