The following information was provided to us by Jason Odd. Thanks Jason!!
The group was active in 1970-1971 for sure. Most likely the band folded in 1971, Gary Lewis left the group and opened a music store in Los Angeles in 1971.
Medicine had a core band of Bill and Gary Lewis on guitars, Bill Boatman (drums), Gordon Shryock (bass), and a fifth member, possibly Dennis Janes.
All the photos I have seen of the group seem to include Bill Cowsill, Lewis, Boatman and Shryock, but at times they were expanded with another guitarist and even a second drummer.
I have no way of telling if the following shows went ahead, but a series of shows were booked in Oklahoma in September-October 1970.
From a poster I have seen, Medicine were billed as 'direct from California the Rock and Roll show Medicine - starring in alphabetical order: Bill Boatman, Bill Cowsill, Gary Lewis, JJ Cale, Jim Karstein, Junior Markham, Gordon Shryock, and Dennis Janes. [... ironic to note that Dennis Janes' name is not in alphabetical order, but I digress...]
The tour took in The Happy Medium at 1763 S. in Tulsa, on Monday September 21, to Saturday 26th.
Sunday September 27, 1970 they moved on to Dutsche's Party Barn at 8855 E. 91st in Tulsa.
On Saturday October 10, 1970 they moved to Bartlesville Civic Center. These run of shows in Oklahoma were sponsored by Rock Talent Club presented by Machine Productions.
Cale, Jim Karstein, and Junior Markham dropped out of the tour, and the one existing poster I have seen has their names and likeness blackened out, although you can just make out their names.
JJ Cale ended up in Nashville in late September and early October to cut tracks for what would be his debut album. I understand that these tracks were cut in studio down-time (i.e. at night) and were a speculative deal that he and his manager had decided to act on, which is why Cale bailed from the tour. I assume Markham and Karstein quit due to Cale's absence.
Why did they relocate to Oklahoma, I assume to get away from the Hollywood scene, plus Oklahoma (well Tulsa) was starting to open up as a recording center and potential youth market for live music. (although that didn't really pan out) Boatman and Shryock were from there and had travelled to LA following Leon Russell and JJ Cale in the 1960s. As far as I recall both Boatman and Shryock worked as members of Gary Lewis group the Playboys in the 1960s.
Billy Cowsill - guitar
Gary Lewis - guitar
Bill Boatman - drums
Gordon Shryock - bass
Dennis Janes - ???
Steve Calandra - bass
JJ Cale - can play guitar, piano, bass and drums
Jim Karstein - drums, percussion
Junior Markham - Harmonica
No known recordings