A 16-year-old boy has been charged after rocks were thrown at an ambulance, cars and pedestrians in the Melbourne suburb of Carlton last night.

The paramedics were travelling with their lights and sirens on when the windscreen was struck by a large rock.

Luckily it did not penetrate the glass and no-one was injured.

But it did leave a tennis ball-sized indentation in the windscreen.

Paramedic Shaun Urie says he could have been seriously hurt.

"We're very thankful it didn't go through, given that the projectile would've entered around my left chest area, had it actually penetrated the windscreen," he said.

The crew changed vehicles and continue working.

Police believe the believed the rock was thrown from a multi-storey apartment block in Nicholson Street.

A number of pedestrians and other cars were struck.

A 19-year-old man was questioned by police and cleared of any involvement.

A 16-year-old boy has been charged with reckless conduct endangering life and has been bailed to appear in the Children's Court in April.