Domoic acid (DA), structurally related to glutamic and kainic acid, mainly generated by Pseudo nitzschia diatom. It often contaminates halobios such as fish and seashell and cause the Amnesic Shellfish Poisoning in human beings with the consumption of foods contaminated by DA. DA has been detected from seafoods worldwide. As the frequent occurrence of red tide and outbreak of human poisoning, more and more studies focus on DA, especially on its excitotoxicity. The producing alga, physico - chemical properties, natural contamination of seafoods, information on human poisoning, toxicity and analytical methods of DA are reviewed.