Section 11, Article II, RA 9165 of the Philippine Constitution is titled "Possession of Dangerous Drugs." According to the University of Minnesota Human Rights Library which hosts an archived copy of RA 9165, Section 11 details the penalty for possession of dangerous drugs, as well as the quantity of drugs that incurs the penalty.
The first paragraph of Section 11 states specifically, "The penalty of life imprisonment to death and a fine ranging from Five hundred thousand pesos (P500,000.00) to Ten million pesos (P10,000,000.00) shall be imposed upon any person, who, unless authorized by law, shall possess any dangerous drug in the following quantities, regardless of the degree of purity thereof:" The specific amounts that incur this penalty are then detailed. If the quantity is less, the second half of the section details the appropriate penalty.
Section 11 lists the following dangerous drugs: opium, morphine, heroin, cocaine, methamphetamine hydrochloride or "shabu," marijuana or marijuana resin oil, ecstasy, LSD, or any other similarly designed drugs and their derivatives. The full list is derived from the 1971 Single Convention on Psychotropic Substances. These drugs may be allowed if they have therapeutic value, but there will still be a penalty if you possess a quantity far beyond the therapeutic requirements.