Seafood and vitamin C taken together may cause poisoning. Seafood contains the chemical element arsenic, and the arsenic content of normal seafood consumption is extremely small. Due to increasing environmental pollution, there may be excessive arsenic content in seafood, plus taking high doses of vitamin C, which will lead to a complex chemical reaction between vitamin C and arsenic, turning into toxic trivalent arsenic, causing a toxic reaction. The vitamin C content of health products in general daily life is not high, and it is relatively safe to take vitamin C appropriately as well as to master the time of taking it.