Ingestion of saxitoxin can cause numbness of the oral mucosa within how long?

• A. 5 minutes
• B. 15 minutes
• C. 30 minutes
• D. 60 minutes

Answer: (C)

Saxitoxin acts quickly by blocking voltage-gated sodium channels in nerves, which stops nerve signals and leads to numbness and tingling. After ingestion, it’s absorbed through the gastrointestinal tract and neural symptoms appear as the toxin reaches the oral region. The typical onset for numbness of the oral mucosa is about thirty minutes, reflecting the usual time needed for absorption and the toxin’s effect on oral nerves. While you can see earlier signs in some people (around fifteen minutes) or later signs in others, thirty minutes is the most commonly reported and expected window. So, thirty minutes is the best answer because it aligns with the common onset timing for oral numbness after saxitoxin exposure.