Potassium supplements are mainly used to treat the people suffering from potassium deficiency in the level of blood due to low diet or diuretics. However there are some of the side effects associated with intake of potassium supplements when taken in excess or due to overdose. Some of the side effects experienced by the people taking potassium supplements are as follows: feeling of nausea, diarrhea, vomiting and stomach upset and these side effects are most common. If an individual is suffering from chest pain, shortness of breath, weakness in muscles, irregularity in heartbeat, confusion, tingling sensation in hands and feet then you must consult a doctor. Pain in stomach and stools becoming black in color are some of the other side effects associated with potassium supplements. Feeling of fatigue, feeling of heaviness and weakness in legs, numbness, and unexplained anxiety are some of the less common side effects of potassium supplements. Pain in throat, abdominal pain, cramps occurring in stomach and soreness are some of the other rare side effects experienced by the person taking potassium supplements. These side effects occur in the initial stages of taking potassium supplements and disappear as soon as your body adjusts to this medicine.