I have had site health check completed, could you help fix

I have had site health check completed, could you help fix the following problem,

'A lot of the reason it is running so slow is you have the largest database table I've ever seen with temporary options (known as transients). Many of these are related to a payment gateway error your site seems to have been experiencing for some time. As WordPress loads and searches these with nearly every hit to the page I do believe you could greatly improve your page load times by cleaning them out.'

regards Nick