MANILA (Reuters) - The head of the Philippines  narcotics control body has resigned after just five months in the job, the second successive official to vacate the post for making statements contracting President Rodrigo Duterte. Retired army general Dionisio Santiago on Tuesday said he quit as chairman of the Dangerous Drugs Board after receiving a call from Duterte s executive secretary, a few days after he publicly said the construction of a 10,000-bed  mega drug rehab  facility was a mistake. Countering illicit drugs is the centerpiece policy of Duterte s presidency and he has repeatedly threatened to kill dealers and users and said he was willing to be jailed for it. His crackdown has killed thousands of Filipinos, but the administration insists it is committed to arresting dealers and rehabilitating users, citing the new facility and the voluntary surrender of 1.3 million addicts and pushers as a sign of its positive intent.  My rule is the boss is always right and if you think the boss is not right, refer to rule No. 1,  Santiago told Radyo Inquirer, adding he had already submitted a two-sentence resignation letter. Santiago had said the government may have miscalculated with the rehab center and should have pursued a practical community-based rehabilitation program. Fewer than 500 people have been admitted to the facility, which was launched last year amid great fanfare and was funded by a wealthy Chinese businessman. Duterte gave Santiago the job in June after the former head was forced to quit after disputing the president s repeated statements that there were more than four million Filipino drug addicts. Duterte has never disclosed the source of that information and some experts say it is exaggerated. Separately, Duterte s new health minister, Francisco Duque, on Tuesday voiced his approval for using marijuana  only for research purposes  in medicine.  He said he would prefer marijuana in  pharmaceutical form  if the country legalized its use.  If it is in raw form, it is uncontrolled, subject to abuse, addiction,  he said at his first news conference.  That is where, I believe, the risks are more profound.  There is a pending bill in Congress to legalize and regulate the medical use of cannabis. 