'“Use by” or “Use before” this would mean that the product should be used before the end of the previous month. For example “use by 06/2008” means that this product should be used on or before 31st May 2008.
Therefore an expiry date of Dec 2008 means that the product should not be used after 31 December 2008."'

e.g. antibiotics 7 - 14 days, other liquids 1-2 months (according to references: 3-6 months), tablets or capsules 6-12 months (according to reference: 'For repacked tablets/ capsules, the expiry date should be 12 months or the manufacturer’s expiry date; whichever is the earlier'

references
http://www.rpsgb.org/pdfs/LEBexpirydates.pdf
http://www.mhsc.nhs.uk/pages/About%2...ed%20Drugs.pdf
http://www.nhsppu.uea.ac.uk/assets/d..._medicines.pdf