Abstract: The invention provides methods for treating tumours, such as solid tumours, in a host. The methods may involve infecting the tumour with an amount of one or more strains of oncolytic virus. The virus will generally be selected to be effective to cause a lytic infection of tumour cells within the tumour. In various embodiments, the host neutrophil response to the lytic infection may be modulated, so that during the course of the lytic infection, the host has an initial neutrophil response and a secondary neutrophil response, these two responses being different in some material respect. For example, the secondary neutrophil response may mediate a greater degree of apoptotic killing of tumour cells than does the initial neutrophil response.