Even though Neptunea contricta appears similar to Batilus cornutus and Rapana venosa, they are different in tetramine content which inhibits the neuronal calcium channel. Therefore, mistaking Neptunea contricta for Batilus cornutus or Rapana venosa, can result in the occurrence of toxic symptoms. Three patients developed nausea, epigastric pain, chest pain, dizziness, blurred vision, dyspnea, hypertension and tachycardia after eating Neptunea contricta. Moreover, consumption of one only piece was sufficient to cause symptoms because each Neptunea contricta has 17.3 mg of tetramine. Accordingly, care should be taken when patients are consuming more than 5 pieces because toxic symptoms such as dyspnea can occur. Moreover, correct species identification is important because the quantity of tetramine varies among sea snail species. Finally, it is important to educate people to remove the salivary glands completely before consuming Neptunea contricta.