Clinical practice has proved that some drugs can reduce the efficacy of levodopa, and some can increase its toxic side effects. In order to maintain better efficacy of levodopa and prevent toxic side effects, drugs that should not be applied simultaneously with levodopa include: (1) vitamin B6: it is a coenzyme of dopa decarboxylase, which can strengthen the activity of peripheral dopa decarboxylase and speed up the rate of dopa decarboxylation into dopamine outside the brain, while reducing the entry of levodopa into the brain and reducing its efficacy. Therefore, the use of vitamin B6 and foods rich in vitamin B6 should be limited. However, it has little effect on the compound levodopa. (2) Lipiodol and its compound preparations (such as compound lipiodol tablets, adafin, hypotensive, hypotensive static, hypotensive etc.) should be avoided because they can increase the depletion of dopamine in the terminal capsule of dopamine neurons. In patients with hypertension without Parkinson’s disease, long-term, heavy medication can also cause Parkinson’s syndrome. (3) Valium and phenothiazines: antagonize the effect of levodopa and should be avoided as much as possible, including chlorpromazine, endorphin, fluphenazine, promethazine, etc. These drugs can cause Parkinson’s syndrome. These drugs can cause Parkinson’s syndrome and postural hypotension, so they should not be used at the same time. (4) Non-selective monoamine oxidase inhibitors can block the inactivation of dopamine and other catecholamines, causing the accumulation of dopamine in the blood, resulting in increased blood pressure and even hypertensive crisis and hyperthermia. Therefore, it is important to discontinue these drugs, such as eugenol, isocarbohydrazide, and phenelzine, at least 2 weeks prior to the use of levodopa. B-type monoamine oxidase inhibitors (e.g., Skinnerin or Kingspine, daily doses below 20 mg) generally do not cause blood pressure elevation. (5) Tricyclic antidepressants: such as amitriptyline, amoxapine, chlorpromazine, etc. can enhance the efficacy of levodopa, but can cause cardiac rhythm disturbances, especially in elderly patients are more likely to occur, should be avoided. The main foods to be avoided are diet, which can also affect its efficacy or may produce adverse effects. (1) High-protein diet: It has been confirmed that certain foods have an effect on the absorption of levodopa, especially a high-protein diet, which can significantly reduce the efficacy of levodopa. Because of some neutral amino acids produced in protein digestion, it can compete with levodopa to enter the blood and affect the absorption of levodopa. Therefore, protein intake should be reasonably distributed, and if necessary, a low-protein diet should be considered. The recommended daily protein intake is 0.8g per kg of body weight, which can eliminate this adverse interaction between food and drugs. (2) Avoid eating choline-rich foods (such as betel nut): Anticholinergic drugs (such as Antan, benztropine, etc.) are commonly used in the treatment of Parkinson’s disease and should be avoided along with choline-rich foods to avoid reducing the efficacy of anticholinergic drugs. (3) In the treatment of Parkinson’s disease, consideration must be given to the possibility that diet may reduce or offset the effect of anti-Parkinsonian drugs or aggravate the disease.