Nerve Growth Factor is an intramuscular neurotrophic drug that targets the peripheral nerves and takes at least 7 days to work, depending on the individual’s condition. The more severe the peripheral nerve damage, the longer it takes to take effect. In the case of Guillain-Barre syndrome, for example, if the damage is mild and myelin loss is the main pathology, the effect will be obvious in about 1-2 weeks. If the degree of nerve damage is more severe and axonal damage is predominant, it may take 4-6 weeks to provide significant improvement. The course of this medication is 2-6 weeks, and can be repeated for 2-3 courses if necessary. The side effects of this drug are insignificant, only local pain, no special treatment is required, and allergic reactions are occasionally seen.