It was used for the first time on our little one who is 2.5 years old. It seems very effective, as even with the first use, we removed all the dead lice with the comb, without it taking more than half an hour from the application. The instructions state that it is suitable even for babies over 6 months old and that it can be left on the head overnight for better results. I believe it is not necessary.
The packaging contains a double comb, with narrow slots, so it does a good job in removing them with thorough combing.
The product is a lotion (the packaging contains a head that works like a spray) and it should be applied well on the entire head, from the roots to the ends. It makes the hair quite oily during application and then requires a very good shampooing, definitely with double rinsing. However, it is very effective and completely odorless, it doesn't smell at all and doesn't bother the child. We will repeat the application in a few days and see.