Why suction cannot retrieve venom
A snakebite is not like a puncture containing a pool of liquid that can be drained. Fangs deliver venom into tissue beneath the skin, where it begins interacting with cells and can spread through the body. The bite opening is tiny, and suction at the surface cannot create enough control over that process to draw out a meaningful amount of venom.
Trying to suck the wound may also injure already-damaged tissue. If the person doing it has cuts or sores in the mouth, venom could contact them there; saliva and mouth bacteria can contaminate the bite as well. Suction therefore adds risks without undoing the bite.
What to do instead
Move away from the snake, then seek emergency medical care promptly. Keep the bitten person as calm and still as possible, and remove rings, watches, or tight clothing near the bite before swelling makes them difficult to take off. Avoid cutting the wound, applying ice, or tying a tight tourniquet; these measures can cause further harm and do not stop venom from taking effect.
The key is to spend the first minutes getting help, not trying to extract what has already been delivered beneath the skin.
