The campaign was aimed at encouraging North Koreans to think about change, conservative South Korean parliament member Song Young-sun said.
The food and medicines were delivered in light-weight baskets tied to balloons with timers programed to release the items above the target areas in the impoverished North, Song said in a statement.
South Korea's defense ministry declined to confirm the move, citing its policy of not commenting on sensitive issues in its dealings with the North.
The food items bore a message that they were sent by the South Korean military and were safe for human consumption but could be fed to livestock to test safety, Song said.
The leaflets also carried news of public protests in Libya against the country's long-time leader, Song's office said.
Analysts say the level of Pyongyang's control over communications and movement of people is too tight to make it likely for North Koreans to rise up to the similar type of protests against their leaders.
South Korea's military has resumed its campaign of speaking directly to North Korean residents after the North bombarded an island near a disputed sea border in November, killing four people including civilians.
Tensions on the Korean peninsula rose to the highest level in years after the artillery attack and the sinking of a South Korean navy vessel in March last year, but the two sides have since renewed a dialogue aimed at easing relations.
Their first attempt at talks broke down earlier in February dealing a setback to plans to resume international disarmament talks with the North.
(Reporting by Jack Kim; Editing by Chris Lewis and Yoko Nishikawa)