The U.S. National Library of Medicine offers these suggestions on how to apply it safely:

• To avoid skin irritation, apply the repellent to clothing.
• Use only a small amount of repellent on exposed skin, avoid contact with the eyes, and wash it off as soon as you are away from possible insect exposure.
• Don't use highly concentrated repellent (DEET), especially on children and pregnant women.
• Never inhale or swallow insect repellent.
• Don't put a lot of repellent on young children's hands, as they may put them in their mouths or rub their eyes.
• Children younger than 2 years old should never wear insect repellent more than once per 24-hour period.