I have been a doctor since March 1970 and a TB specialist since January 1983, and have been practicing medicine for 46 years (33 years as a TB specialist). In the course of using isoniazid for the treatment of tuberculosis, I have always followed the dosing standards for isoniazid in Pediatrics, Practical Pediatrics, Internal Medicine, Practical Internal Medicine and other monographs, and these standards have proven to be safe and effective in practice. “In the era of rampant medical disturbances, a new instruction manual for the use of isoniazid (hereinafter referred to as the “new instruction manual”) appeared, which stated that “the maximum dose of isoniazid should not exceed 300mg/d”. This changed the previous instructions, which puzzled the author. In the 1970s and before, 100,000 IU of penicillin could save a patient with severe pneumonia, but nowadays 1,000,000 IU of penicillin cannot achieve that effect, because any organism has the ability to adapt to the environment, and microorganisms including Mycobacterium tuberculosis are the same. Any good anti-microbial drug is effective in smaller doses in the early stages of use, but as the drug becomes more widespread and widely used and as the years go by, anti-microbial drugs need to be used in larger and larger doses until they become ineffective. The same is true for anti-tuberculosis drugs, which is why there is now an advocacy literature for the use of high-dose isoniazid and high-dose rifampin. The “new instructions” break with tradition and include the words “not to exceed 300 mg of isoniazid per day”. Is it really courageous to buck the laws of biological evolution because conventional doses of isoniazid have more adverse effects than conventional doses of rifampin? The answer is no, the incidence of adverse reactions of regular dose rifampicin is much greater than that of regular dose isoniazid, which is almost free from toxic reactions. Is the statement “daily dose of isoniazid should not exceed 300mg” based on the literature of relevant studies? I have searched a lot of domestic and foreign literature, but I could not find any evidence that “daily dose of isoniazid does not exceed 300mg” is applicable to all people. In the Internal Medicine and Practical Internal Medicine, the dosage of isoniazid in the combination of anti-tuberculosis drugs is considered to be 0.3-0.4g/d for adults and 0.6-0.8g/d for those who take the drug twice a week [3,4]. Among others, the Internal Medicine also expresses: “10-15 mg/(k?d) in children (not more than 300 mg per day). The dose may be doubled for acute cornual tuberculosis and tuberculous meningitis”. In Pediatrics, it is stated as “Primary tuberculosis: 15-20 mg/(k?d) for infants and children; 10-15 mg/(k?d) for children; 20-25 mg/(k?d) for acute cornified tuberculosis and tuberculous meningitis” [5]. In Practical Pediatrics, it is stated as “15-20 mg/(k?d) for infants and children; 10-15 mg/(k?d) for older children; up to 20-30 mg/(k?d) for severe tuberculosis, but the daily dose should not exceed 500 mg”, and in another section of the monograph, it is stated that the daily dose should not exceed 600 mg per day. The issue of daily limit is mentioned in Internal Medicine and Practical Pediatrics, and Practical Pediatrics does not distinguish between pediatric and general children, proposing a daily limit of no more than 500mg to 600mg, while Internal Medicine clearly states “10-15mg/(k?d) for pediatric patients (no more than 300mg daily) “. There are two important points here, one is that the limited target of medication is “pediatric”, and the second is that the content in brackets is to indicate the “limit” for pediatric patients, and does not include the limit for older children and adults. In the Pharmacopoeia of the People’s Republic of China, the dosage of isoniazid is 5-8 mg/(k?d) or 0.3-0.4 g/d for adults, 0.6-0.9 g/d for those who take the drug 2-3 times a week, and there is no statement that the dosage for adults should not exceed 300 mg/d. The Chinese Anti-Tuberculosis Association has proposed the use of high-dose isoniazid for the current treatment of drug-resistant tuberculosis. For adult low-dose isoniazid-resistant TB patients, the dose of isoniazid is 16-20 mg/(k?d). The recommended dose of anti-tuberculosis drugs for children (for children with a body mass of 30 kg or less) in the 2014 WHO Guidelines for Planning and Management of Drug-Resistant Tuberculosis Partner Manual: isoniazid 7-15 mg/kg per day, with a maximum dose of 300 mg per day. The generalized statement that “the maximum dose of isoniazid should not exceed 300 mg/d ” is said to be neither in line with the previous classical literature nor with the modern reality of tuberculosis treatment. Some people may say that isoniazid was discovered in western countries, and Chinese medical experts do not know hydrazid better than western medical experts. However, I would say that Chinese medical experts are more experienced in the use of isoniazid than Western medical experts because China has the largest TB population in the world and Chinese medical experts have more clinical practice and research. There was a “white plague” epidemic in the industrialized West, but isoniazid was not available at that time. Some people may argue that scientific progress is changing rapidly and that the contents of Internal Medicine, Practical Internal Medicine, Pediatrics, and Practical Pediatrics have not kept up with the times, but I agree that many of these works have been updated or are yet to be updated, but the updates must be based on new scientific research and that the authors of the “new instructions” Can the authors of the “new instruction manual” provide a documentary basis for the study that the “daily dose of isoniazid does not exceed 300 mg” is applicable to all populations? Regarding the definition of “pediatric”, different monographs have different or even contradictory definitions, and the author has not found a uniform definition. The Convention on the Rights of the Child, adopted by the United Nations General Assembly on November 20, 1989, defines a child as any person under the age of 18. In the medical field, children between 0 and 14 years old are the object of pediatric research, and the age of members of the Chinese Children’s Organization Pioneer Corps is under 14 years old, while the age of membership in the Communist Youth League is 14 years old or older. According to some scholars, the term “pediatric” refers to children within 3 years of age. In pediatrics, children are classified according to their developmental characteristics: fetal period, infant period (0-1 year), early childhood period (1-3 years), preschool period (4-6 years), elementary school period (7-12 years), and secondary school period (13-17 years). The dosage of isoniazid for children with tuberculosis is divided into two dose groups, infants and children, in Pediatrics, and two dose groups, infants and older children, in Practical Pediatrics. However, I believe that “children” should not exceed at least the preschool age (within 6 years), and the 2014 WHO Guidelines for Planning and Management of Drug-Resistant Tuberculosis (DR-TB) partner manual, in which “children with a body mass of 30 kg or less” is also worthy of reference. This definition is open to debate. Is the statement that “isoniazid dose not more than 300 mg per day” is applicable to all people a careless mistake? Or is there another purpose? Since the “new instruction” appeared at the time of the “medical trouble”, it cannot be ruled out that the businessman manipulated it as a self-preservation technique. Isoniazid is rapidly absorbed orally, reaching peak blood concentration in 1 to 2 hours, with a half-life of 0.5 to 1.0 hours for fast-acetylating individuals and 2.0 to 4.0 hours for slow-acetylating individuals [4]. The above has been described. The preceding section already states that “isoniazid at a dose not exceeding 300 mg per day” is not applicable to all people. I don’t know how the “new instruction” removed the parentheses from the sentence “0.3-0.4g/d for adults, 0.6-0.8g/d for twice weekly doses, 10-15mg/(k?d) for children (not more than 300mg daily)” in the Internal Medicine. The parentheses were removed and a “,” was added in the middle? The content of “0.3~0.4g/d for adults” was also removed, confusing the difference between the drug doses for infants, older children and adults, and limiting the dosage of isoniazid for older children and adults not to exceed the maximum limit for children, which obviously lacks pharmacokinetics, pharmacodynamics, toxicology, clinical adverse reaction observation and other pharmacological This obviously lacks pharmacological basis such as pharmacokinetics, pharmacodynamics, toxicology and clinical adverse reaction observation. This obviously lacks pharmacokinetic, pharmacodynamic, toxicological, and clinical adverse effect observations. While the “new specification” protects the interests of those who sell drugs of unstable quality, it hurts patients, physicians, and national TB control strategies. The low isoniazid combinations that emerged from the “new instructions” are also being used and promoted nationwide by the appropriate authorities. We must clearly understand that the resistance rate of isoniazid is much higher than that of other anti-tuberculosis drugs [1], and the reasons for this deserve deeper investigation and introspection. V. Recommendations TB prevention and control workers, clinicians and providers of anti-tuberculosis drugs must clearly recognize the serious situation of TB control, especially the serious epidemic situation of drug-resistant TB. If the formation and prevalence of drug-resistant TB is artificially exacerbated by our work mistakes, how can we face the social and historical responsibility we have assumed? If the authors of the “new instructions” cannot provide sufficient evidence from the literature, please correct the erroneous instructions. Those low-dose combinations of isoniazid also need to be revamped. A new approach that is in line with the laws of nature is innovation, and a corrective approach that is in line with the laws of nature is also innovation. Contemporary medical pharmacology and management of tuberculosis should have the courage, mind and responsibility to seek truth from facts.