A Melbourne dentist is suing a patient for defamation over an online review. Mr Patient let loose a low star rating and a personal attack against Mr Dentist, apparently following a highly priced quote for a filling.

Responding to a bad review is tricky. When to ignore? When to respond politely? When to go completely legal at them? The right approach requires a careful blend of PR strategy and legal advice. You'd generally only favour a legal approach in a pretty serious case. But those cases do exist. Here are our top 5 points to consider when you get a negative review.

1. Where is the review posted? Most review platforms will take down reviews that violate the platform guidelines. Personal insults, vulgarities, hate speech or threats might be candidates for removal.

2. Is the review about a business or an individual? Individuals and small businesses (fewer than 10 employees) can claim for defamation. Big businesses can't, although in some cases they might have other options.

3. What does the review actually say? Many negative reviews would be defensible against a defamation claim. Truth and honest opinion defences could apply, as could others.

4. How serious is the defamation? This is an important one. The risk with legal action is that you end up drawing more attention to the negative review, especially if there is press coverage. Look at Mr Dentist now everyone who reads the Age knows he got a bad review. And suing a customer isn't always a great look, reputationwise.

5. Can you identify the individual who posted the review? Platform owners generally won't share user details without a court order. Obtaining a court order for disclosure is a possibility, but it can be a pretty expensive exercise. Suing the review platform might also be an option if they won't remove a defamatory post. But they'll generally put up a decent fight because negative posts are a big part of their business model. A strong and wellresourced defence will increase the time, expense and risk of any claim.