A man’s kidney failure has been linked to his excessive iced tea habit—but don’t worry, you’re probably not approaching the danger zone. The 56-year-old Arkansas man was drinking 16 glasses of the stuff daily, amounting to a gallon every day,the AP reports. Black tea contains a lot of a compound called oxalate, which can lead to kidney issues, LiveScience reports.

“With 16 cups of tea daily, the patient’s daily consumption of oxalate was more than 1500mg—a level that is higher than the average American intake by a factor of approximately three to 10,” scientists say.

The man was hospitalized last year, and his urine contained lots of the calcium oxalate crystals involved in kidney stones. He was put on dialysis and he may be on it for life, doctors note.

“We are not advising against tea consumption,” a researcher says. “If you are healthy and drink tea with moderation, it should not cause damage to your kidneys.”

In fact, past studies have suggested that a more reasonable amount of tea can actually fight kidney stones, an outside researcher tells Reuters. Still, many of us apparently consume too much oxalate, which can be found in spinach, chocolate, nuts, and wheat bran, among other foods. While experts don’t recommend going beyond 50mg per day, the average American consumes 152mg to 511mg, researchers note.