Kamagra is a very effective medicine for the treatment of erectile dysfunction. The main active ingredient in this drug is sildenafil. This drug increases the amount of blood in the blood vessels of the penis so that arousal for intercourse is achieved and the sexual erection lasts longer. The proper time to take this medicine is 30 minutes before sexual intercourse. The effect of this medicine lasts for at least 3 to 4 hours after taking the medicine. This medicine should be taken orally.