Supplements are beneficial for many health-related issues, but when taken in certain combinations they can be harmful. Experts warn that taking high doses of vitamins E and K at the same time could lead to dangerous blood clots and kidney damage.

Dr. Sean Orman, a pain management specialist based in Arizona, tells SheFinds that while vitamin E and vitamin K are both important to your health, these fat-soluble supplements taken together in high doses can increase the risk of blood clots. One study stated that the adverse reaction of taking these vitamins in tandem was first noted 50 years ago, warning that “given both nutrients’ critical involvement in coagulation, in extreme cases, this interaction could result in abnormal blood clotting.”

Nutritionist Jesse Feder adds that taking high doses of any fat-soluble vitamin like these, which also include vitamins A and D, could damage your kidneys and liver. “While taken in normal amounts, vitamins A, D, E and K are harmless,” he explains. “But certain supplements may contain high amounts of them, which can be damaging to our liver and kidneys.”  The Florida-based dietitian says that fat-soluble vitamins are not excreted though urine and this could lead to a buildup of the vitamins in the kidney and liver, especially when consumed in combination.

According to Livestrong, the Journal of the American Medical Association published an article that claimed certain supplements could actually increase your risk of death if taken in high doses. Although this increased risk of death is only associated with certain supplements, such as vitamin A, there is a wide variety of negative symptoms associated with overdosing on any vitamin. For example, overdosing on vitamin B6 can lead to permanent nerve damage.

The bottom line is that most supplements when taken in the recommended doses are potentially safe, but exceeding these amounts or combining different supplements may pose potential health risks. In general, check the ingredients and side effects carefully and avoid taking supplements together that have the same effect on the body, or counteract each other. It’s always safest to check with your doctor when taking any supplements to see if there could be an interaction between supplements or with any medication you are taking.