What should one do, and why? Anyone asking such questions--and everyone does so hundreds of time each day--is concerned with ethics. Product development and testing raise many ethical questions. Particularly since the rise of 'green consumerism', these are of increasing concern to people outside the cosmetics industry, and so should be of interest to those inside it. The major problem seems to be that of reaching agreement on moral and ethical issues. Overcoming this problem involves investigating what is meant by 'ethics', and how decisions depend not on facts but on 'facts-as-perceived'. These in turn depend on many factors, with one's philosophy being the most fundamental. The range of philosophical options is reviewed and it is proposed that wider discussion is the only just way to achieve agreement. Yet some things are not negotiable. There are certain key moral concepts in terms of which discussion must take place for it to be relevant. In ethics of human testing, 'respect for others', that is, avoiding exploitation, is the principal one. Some synthesis of the key moral concepts like that of Immanuel Kant is therefore recommended as the soundest and most widely acceptable basis for the necessary discussion. Defining the responsible use of human subjects covers a range of issues, moral, historical, legal and professional. For example, there may be ethical difficulties in deliberate damage induction as in SPF and irritancy testing. But above all, to avoid exploitation, there is a moral and also a legal requirement that subjects are truly volunteers. This is the basis of the concept of 'informed consent', required but not generally explained in current professional codes of practice. It is unjustified to exploit those who may be under duress, such as 'in-house volunteers' and those with low incomes. Hence in conclusion, criteria for obtaining valid informed consent are briefly reviewed. By considering issues such as these, we can help ensure that cosmetic scientists are true professionals, that is, those who recognise and are concerned with the ethical basis of their work.