This study evaluates, among study patients with lymphoma or myeloma undergoing autologous SCT, whether cooling oral mucosa with a cooling device compared with ice cubes/crushed ice or ice pop succeeds in reducing the degree of oral mucositis (OM) according to the Oral Mucositis Assessment Scale (OMAS) total,degree of OM according to World Health Organisation (WHO), tolerability of either cooling method. The study is also aiming to , patients subjective experience of OM, rating of general quality of life and oral pain, number of days with total parenteral nutrition (TPN), number of hospital days, total dose of opioids, and C reactive protein during time in care.