This principle states that if a practice is considered consistent with the guidelines of medical professionals, there isn't no evidence of negligence or wrongdoing. in this context practice or practise

In the context of this sentence, both "practice" and "practise" could be used. However, "practice" is more commonly used in American English, while "practise" is more commonly used in British English. So, the sentence would be:

"This principle states that if a practice is considered consistent with the guidelines of medical professionals, there isn't no evidence of negligence or wrongdoing." (American English)
or
"This principle states that if a practise is considered consistent with the guidelines of medical professionals, there isn't no evidence of negligence or wrongdoing." (British English)

In this context, the correct term would be "practice," which refers to the act or process of carrying out a profession, such as medicine. "Practise" is more commonly used as a verb meaning to perform or engage in a specific activity repeatedly to improve one's skills.