Constipation One of the most common side effects of taking excessive calcium is constipation. Constipation for prolonged period of time can lead to stomach ulcers, pain and bloating. It is a good idea to take magnesium and vitamin D supplements to ensure that there is proper absorption of calcium. Flatulence One very embarrassing and annoying side effect of consuming excess calcium is the formation of gas or flatulence. Stomach Problems Taking excess calcium can cause gastrointestinal problems like nausea, vomiting and abdominal cramps. Formation of Plaque Too much calcium in the blood can lead to the accumulation of plaque in the arteries. This can exert a hypertensive effect on the heart muscle, which in turn increases the risk of stroke and heart attack. Risk of Heart Disease Some studies and clinical trials link excess intake of calcium supplements with increased risk of heart diseases. However, the results of such studies are not conclusive. To be on the safer side, it is best not to consume more calcium than the recommended daily dose. Kidney Stones If there is too much calcium in your blood, it might lead to a condition known as hypercalcemia. This condition which is characterized by vomiting, fatigue, loss of appetite and persistent thirst can negatively impact kidney functions. High levels of urinary calcium leads to the formation of kidney stones. People who are already suffering from kidney problems should consult their doctor before taking calcium supplements. Risk of Prostate Cancer Some studies have found a link between calcium intake of 600 mg per day, with an increased risk of prostate cancer. Although the research is far from conclusive, it is better to observe caution and limit the intake of calcium. Calcium Toxicity Too much calcium in the blood (over 2500 mg) may cause calcium toxicity. It can develop into abnormal deposits of calcium in tissues, which is harmful for the body. Interactions with Medicines Taking excess calcium can cause some adverse interactions with certain medications and so it is best to take the advice of a doctor before using calcium supplements. Excessive intake of calcium can increase the reaction to digoxin, a drug which is used for the treatment of irregular heartbeat. It can also interfere with the body's ability to absorb certain antibiotics like ciprofloxacin, norfloxacin, tetracycline etc. Excess calcium intake may interfere with the absorption of alendronate, a medication which is used for the treatment of osteoporosis. Other Side Effects Dry mouth, confusion, severe fatigue, nausea, irregular heartbeat, metallic taste in mouth, loss of appetite and dizziness are some other side effects of taking too much calcium.