Numbness in thumb is usually due to the decrease of blood supply in this area. There are many reasons for this like carpal tunnel syndrome, peripheral nerve disorder, arthritis, in diabetis also this problem occurs etc. Due to smoking also your nerves get weak and this problem occurs. So in such I would recommend you to consult some neuro physio who can diagnose it and can give you the exact reason for numbness. In the meantime to get relief from this let me recommend you some home treatment: 1. Take a warm water in a small tub or bucket. Place your hand in it for 5 - 10 minutes and then using other thumb massage your affected area. As it will increase the blood flow of the numb area and give your relief. 2. After taking above hot fermentation perform some exercises like: Elevate your hand and then make a fist and open it, use use spongy (smily) ball press it tightly as much as you can and then release, you can also do finger counting exercise with thumb, and tie a rubber band over thumb and then stretch it by doing flexion, abduction movements. 3. Once done with the exercise relax yourself by keeping your hand in elevation position for 10-15 minutes. Please take some precautions: 1. Avoid drinking and smoking as much as you can. 2. Avoid excess eating, specially citrus fruits, fat products like ghee butter etc., diary products for time being, junk food, fry food etc 3. You can have healthy food items like bananas and leafy, green vegetables etc. 4. Nowadays in winter do not keep your hand open, try to wear glooves and keep them warm. 5. Keep your arm elevated to increase blood supply. 6. If there is very much numbness you can have hot cold pack by checking if it is not more hot or cold from other hand. Apply in the ratio of 2:1. 7. If require then only take medicine. Please follow the above treatment you will get a relief.