Marine toxin detection methods can be grouped into two main categories, analytical methods, which are based on the physicochemical properties of the compounds of interest, and biological methods, which include a biological component in the detection system. Regarding biological methods, two different classes should be discriminated due to their toxin detection characteristics, biochemical methods, and functional/receptor-based methods. Receptor/target-based assays use the interaction of a receptor or biological target with a toxin or group of toxins to sense their occurrence. For functional and receptor/target-based assays, there is a better chance that the result provides a good estimation of sample toxicity. Animal bioassays consist of the administration of a sample extract to an animal and observation of the appearance of toxicity signs. Target-based functional methods provide information about the modification of the activity of a biological target by the presence of the toxin of interest.