No olive oil, No OTC products unless you want your son to run the risk of being deaf for life. If he has an ear infection and current medication is not working with tubes in the ears go back to the doctor NOW and get something else. Even if he didn't have tubes in the ears at 4 years old you don't want to play doctor and run the risk of making things worse. Amoxicillen is only one class of antibiotic - there are many others out there. It is generally a broad spectrum 'weaker' antibiotic that can treat most kinds of infection. However there are many kinds of infections and sometimes the first use of an antibiotic needs to be replaced with a stronger or different antibiotic in order to get at the infection. I doubt that the doctor did much more than look in the ears and see the signs of infection - no infectious material was drawn out and tested for its type. Doctor went with the most common known bacteria that cause ear infections and treated that saving lots of money and time. That is common practice. If all the millions of ear infection patients were put through tests labs would be over worked to the point that other crucial cases would not get done and people would die. Common practice is to treat for the most common infection first, wait and see and if it does not start to clear up or clear up then go for something stronger, better. It is preferred not to stick needles in 4 year old ears to draw out puss to run it through tests. 4 year olds tend to get all bent out of shape with sharp objects poking them - so do many 40 year olds as well. Call the doctors office and tell the doctor, he will most likely want to see your son again, or may, over the phone, prescribe a different antibiotic. Once he knows that the first course of antibiotics are not working he will try other things - but he has to know first before he can raise the ante.