Yes, you can give Tylenol for children aged 2-11 years to a child who is 20 months old. The recommended dose is calculated based on the child's weight. Usually, Tylenol for children in this age group has a concentration of 160 mg/5 ml. If this is the case, you can give the child 5 ml by mouth every 4 to 6 hours as needed, with a maximum of 5 doses in 24 hours. If the concentration of your Tylenol is different, please provide the correct information so the dose can be recalculated for your child. Feel free to reach out if you have any other questions.