New 12-alkoxy-3,7,11-trimethyl-dodecatetraenes are of interest as perfume and flavor materials having a mandarin and orange effect. The new compounds can be manufactured relatively simply, e.g. by vinylating or ethynylating the corresponding new, but easily accessible, 7-alkoxy-6-methyl-hept-5-en-2-ones and subsequently partially hydrogenating the products, reacting the resulting allyl alcohols with acetoacetic acid esters or diketenes at an elevated temperature, again vinylating or ethynylating the alkoxyketones obtained, then partially hydrogenating the products, and eliminating water from the 12-alkoxy-3,7,11-trimethyl-3-hydroxy-dodecatrienes thus obtained.