<s>[INST] my child is 3 1/2 years old he has cough not in a very chronic but in last two three months he has little mucus in his lungs continuously docter tested and esinophill count will be 540 and esino phill is 08 % he said he has allery little .also his haemoglobin is less 9.6,ESR 25 he recommended montair 4 for use 4-5 months .it has been 5 days already i want to ask that docter said if we give this medicine the problem will  not continue and his immune sustem will become good? my question is there is side effect of medicine in long term use and it will be really beneficial for my kid ?the doctor also recommended allergy panel test.it is very expensive. [/INST] Hello. Thank you for asking at Chat Doctor. I went through your sons' history. I would like to know a few more details like - Does he have nose allergy symptoms (nasal congestion, running nose, sneezing)? Does he have skin allergy or any other allergy? Has he ever had wheezing? Did he any time required nebulization? Does he have anyone in family with allergies? Is he exposed to smoke? However, from your given history, I would like to make following suggestions to you:1. In reply to your main question - montelukast safety - Yes, it is considered one of the safest Chat Doctor.  </s>