Ronaldo believes the plight of Adriano should serve as a warning to Mario Balotelli not to waste his talent.
The Italy international has arguably made the headlines more for his behaviour off the pitch than on it and Ronaldo has not forgotten about what happened his former Brazil team-mate.
"We have all done some stupid things at some point in our lifes, but it's important to realise when it's time to quit. I remember the example of Adriano, although that is not necessarily related to Balotelli's situation, because it's a bit different," the retired Selecao legend told La Gazzetta dello Sport.
"Adriano had crazy skills and a fantastic physique. He could do whatever he wanted on the pitch. However, at some point he simply couldn't do it anymore. So the only advice I can give Balotelli is to focus on his football and not to throw away his talent.
"Balotelli has a certain talent, the way he strikes the ball and scores goals. He's not there yet, though. He can still improve and has plenty of time to do just that. But his age must not become an excuse.
"Balotelli has everything to become a great, but he must win titles first. The difference between becoming a champion or just a good player is whether you win important trophies."
The 22-year-old will be looking to add his first piece of silverware with Italy's senior side to his trophy cabinet this summer as they take part in the Confederations Cup.