The following would not be expected to cause any ill-effects:
* Ink: ball-point pens, felt-tip pens, and fountain pens contain so little ink that there is not enough to cause poisoning if it is sucked from a pen. Some inks may cause soreness in the mouth. Large amounts of ink swallowed from a bottle could be irritant, but serious poisoning has not been reported.
* Pencils and wax crayons: "lead" pencil is not lead but graphite, which is harmless.
* Silica-gel drying crystals used to keep things dry by absorbing moisture.
* Thermometers: if the end is bitten off a glass thermometer and the contents swallowed the small amount of liquid will not cause poisoning. Metallic mercury will pass through the body unchanged. The broken glass may cause injury.
What to do
Give a cup of water. There is no need to do anything else.
If the patient has bitten a thermometer, check that there is no broken glass inside the mouth.