The wide availability of the drugs that are marketed for children can make them seem deceptively safe. Young children are much more likely than adults to have adverse drug reactions, so giving your preschooler medications – even "herbal" medicines – is not to be taken lightly. Sometimes, a little cough or some discomfort is preferable to the risks involved in using strong medicines to treat common childhood illnesses.

Aspirin 

Never give your child aspirin or any medication containing aspirin. Aspirin can make a child susceptible to a rare but potentially fatal illness called Reye’s syndrome. Aspirin is sometimes referred to as "salicylate" or "acetylsalicylic acid." Read labels carefully, and ask your doctor or pharmacist if you're not sure whether a product contains aspirin.

Over-the-counter cough and cold medicines

Never treat children younger than two years of age with over-the-counter cough and cold medicines unless specifically directed to do so by your pediatrician. These drugs can be harmful when a child mistakenly gets more than the recommended dose. If your preschooler is miserable with a cold, try a humidifier or some other home remedies before rushing in to give such medications.

Anti-nausea medications

Don't give your child an anti-nausea medication unless his doctor specifically recommends it. Children usually handle most bouts of vomiting without any medication. If your child is vomiting continuously and begins to get dehydrated, contact his doctor for advice on what to do.

Double Doses of Pain Reliever

Some pain relievers, like acetaminophen (Cetal) or ibuprofen (Brufen) are safe to give your infant in moderation for painful conditions, but pain relievers can also be hiding in preparations like cold and cough medicines, putting a risk for dangerous double dosing. It's always a good idea to check with your pediatrician.

Expired medications

Before you give any drug to your baby, and make sure to check the "use by" date stamped on the bottle. After the use-by date, medications may no longer be effective and can even be harmful. If it's out of date or looks suspicious, discard it.

Adult medications

Giving your child a smaller dose of medicine meant for an adult is dangerous. Most adult over-the-counter preparations contain concentrated ingredients, additives and preservatives that may be harmful by themselves or interact with substances your infant is already taking. If the label doesn't indicate an appropriate dose for a child, don't give that medication to your preschooler.

Medications prescribed for someone else

Give him only medicine prescribed for him and his specific condition. Drugs that worked well for other people (like a sibling) may be ineffective or even dangerous when given to your child.

Ephedrine

Never take or give your child the ephedra or ephedrine which is originally a Chinese herb. In adults this herbal decongestant has been linked to high blood pressure, irregular heartbeat, seizures, heart attack, and strokes. Always let the doctor know about any herbal remedies your child is taking before she prescribes a medication.