Caffeine is the world’s most popular stimulant. Some 90 percent adults in North America consume it every day, generally in coffee, tea, chocolate, soft drinks, or energy drinks. For women with PMS, however, caffeine can cause or worsen insomnia and irritability.

Caffeine stimulates the nervous system and is associated with host of positive effects: it makes you more alert and wakeful, produces clearer and faster thinking, increases your focus, and provides better body coordination. It also improves mental and physical performance. A number of studies over the years have shown that athletes who ingested or received a dose of caffeine had more endurance than those who did not.

Caffeine is also used in combination with medicines to increase their effectiveness. For example, pain relievers are more effective and quick-acting because caffeine helps absorb headache medication.

But too much caffeine can cause irritability, muscle twitching, and even heart palpitations. As few as three or four cups of can cause a condition known as caffeine intoxication, in person becomes agitated, nervous or excited, flushed in the has a rambling flow of thought and speech, and an irregular heartbeat.

You can lessen your PMS symptoms by reducing the amount caffeine in your diet. That means you should cut down or eliminate coffee, tea, chocolate, colas, and energy drinks from your diet, in the luteal phase.