Will a turtle die from drinking a small amount of amoxicillin solution?

Generally, with a reasonable dose of amoxicillin used for a medicinal bath, a turtle that drinks a small amount of the bath water will not have a big problem, because amoxicillin itself is not harmful to turtles. Only an excessive dose causes side effects; if the turtle cannot metabolize it, the drug builds up in the liver and kidneys, causing liver and kidney toxicity that can eventually kill the turtle.

However, the amoxicillin in a medicinal bath is diluted with water, so even a little drink at a reasonable dose will not have much effect; continued observation is recommended. On the other hand, if a turtle is allergic to penicillin-type drugs, it could very well die from an allergic reaction, and that possibility exists.