Max possession is determined by you and your doctor. If you need more than 2 ounces, then you can have more. Once you go beyond the 2 ounces, if there is an issue, the burden of proof is on YOU to show why you needed that amount. Please educate yourself and read the State constitution.

Colorado: Department of Public Health and Environment, Colorado Medical Marijuana Registry

(a) A patient may engage in the medical use of marijuana, with no more marijuana than is medically necessary to address a debilitating medical condition. A patient's medical use of marijuana, within the following limits, is lawful:
(I) No more than two ounces of a usable form of marijuana; and

(II) No more than six marijuana plants, with three or fewer being mature, flowering plants that are producing a usable form of marijuana.

(b) For quantities of marijuana in excess of these amounts, a patient or his or her primary care-giver may raise as an affirmative defense to charges of violation of state law that such greater amounts were medically necessary to address the patient's debilitating medical condition.