Yes, Syria Used Chemical Weapons
Josh Rogin has the whole of the secret State Department cable on poison gas in Syria at The Cable blog at Foreign Policy. Rogin's report embarrassingly discredits official assurances that no chemical weapons were used in Homs on December 23.
The [US Istanbul] consulate's own contacts reported that victims had symptoms that were "consistent with poisonous gas inhalation." A reporter for the Syria Life Network (SLN) told the consulate staff the symptoms included burning eyes, temporary blindness, relaxed and numb joints, unresponsiveness, nausea, unconsciousness, difficulty breathing, and temporary paralysis affecting the spine.
One contact interviewed by the consulate staff reported that the agent used was suspected to be Agent 15, a chemical thought to be related to BZ, an incapacitating agent controlled under schedule 2 of the Chemical Weapons Convention, to which Syria is not a party. This contact said the agent was treatable with Visostgman-Physostigmine, Alberodquisan, and Vitamin B6. The use of the drug Atropine worsened the condition of the patients, this contact said, which would be consistent with the theory that a BZ-like compound was used.
… [C]ontacts reported to the consulate that seven people were killed by the dispersed gas and 50 more victims were treated in a field clinic. The seven dead were buried and videos of their burial "clearly show the absence of visual injuries," the cable stated.