Select Query Showing Too Many Records

I have two tables, bad design, not my choice of the way it's set up.

Table a has Fields 1-2, dups allowed in all fields. No pk was originally assigned.
Table b also has the same fields 1-6, but also has field 6.

Table a has all of the records in question, table b only has some of the records from table a but does not have any records that are not in a.

Something like this.
Table a

Field1 Field 2 Field 3 Field 4 Field 5
John Shirt blue denim button
Mark pants green straight
John Shirt blue silk button


Table b

Field1 Field 2 Field 3 Field 4 Field 5 Field6
John Shirt blue denim button new
Mark pants green straight used


If I query the two tables, a left join to b, then I get the correct number of total records. If I select any records from b, then the total records goes higher than there are, even for the two combined, listing the same record multiple time.

Any suggestions are appreciated. I am a blood bank lab person, not an IT person, or DBA, so simple responses are greatly appreciated.