Calcium and iron supplements are not recommended to be taken together, and it is best to take them separately to avoid affecting the absorption of calcium and iron. Generally calcium supplements are taken after dinner and within 1-2 hours before bedtime, and iron supplements are taken in the morning between meals. The best time to take calcium supplements is after dinner and before going to bed. Because calcium absorption needs the help of stomach acid, calcium is better absorbed when it is taken during or after a meal when stomach acid is secreted. Some people think that they may lose more calcium at night, so they can take calcium supplements before bedtime or after eating slightly before bedtime. Iron supplementation is usually in the morning between meals, because iron supplementation on an empty stomach will cause gastric stimulation, and iron supplementation immediately after meals will be poorly absorbed, it should be chosen between meals, such as 1-2 hours after meals, when there is still food in the stomach for iron supplementation, which can reduce stimulation and also ensure absorption. If there is no gastrointestinal irritation reaction to iron supplementation, you can supplement iron on an empty stomach, when iron absorption is best. It is recommended to take calcium and iron supplements under the guidance of a doctor to avoid causing damage to the body.