接触不良用英语怎么说

"Adverse contact" is the equivalent expression in English for "接触不良". It refers to a negative interaction or effect that occurs when two things come into contact with each other.
For example:
The new medication caused an adverse contact with his existing health condition.
The company experienced an adverse contact with the public after the scandal was revealed.
中文翻译：新药物与他现有的健康状况发生了不良接触。 公司在丑闻被曝光后与公众发生了不良接触。