Hello, I understand your feeling Repeated cold is not very common in a person unless and untill he is allergic to a particular thing. Make notice of the substance that with which you face this problem and try to avoid it. And if you're such susceptible then taking precaution would be a better option than taking antibiotics. Precautions like avoiding dust and pollution expsoure or going out with proper covering of nose, avoiding cool drinks and exposure to cold, if you're in an AC enclosure you need to set the temp to which you're comfortable with. Thank you