Al Jazeera is repeating allegations that Syria has used chemical weapons in Homs, although it indicates that it cannot confirm the allegations. According to the article: "Activists also told Al Jazeera that scores of others were affected in al-Bayyada neighbourhood. Side effects reported include nausea, relaxed muscles, blurred vision, and breathing difficulties."
While the Syrians probably have several different types of chemical weapons, the only one I've seen specifically named as been sarin, a form of nerve gas. According to the CDC, the symptoms of exposure include:
People exposed to a low or moderate dose of sarin by breathing contaminated air, eating contaminated food, drinking contaminated water, or touching contaminated surfaces may experience some or all of the following symptoms within seconds to hours of exposure:
Runny nose(Underline added).
Small, pinpoint pupils
Drooling and excessive sweating
Nausea, vomiting, and/or abdominal pain
Slow or fast heart rate
Low or high blood pressure