The accident, which happened at 12.15pm today on the A259 in Brookland, near the Woolpack Inn, has caused the road to be closed in both directions.
Slow traffic has been reported between the pub and Lamb Farm Cottages, drivers are advised to approach with caution.
Police spokesman Steve Knight said: "Kent Police was called at 12.14pm following a single-vehicle collision on the A259 at Brookland, close to the Kent and Sussex border.
"Officers from the Serious Collision Investigation Unit are in attendance and a road closure is currently in place.
"The two occupants of the vehicle, a man and woman, have been taken to hospital for treatment.